HomeMy WebLinkAboutResolution 5112 Accepting Preferred Alternative for Davis Lift Station and Norton East Ranch Outfall Sewer Interceptor 130
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COMMISSION RESOLUTION NO. 5112
A RESOLUTION OF THE CITY COMMISSION OF THE CITY OF BOZEMAN,
MONTANA,ACCEPTING THE PREFERRED ALTERNATIVE IN THE PRELIMINARY
ENGINEERING REPORT AND AFFIRMING ADEQUATE RESOURCES TO
CONSTRUCT AND MAINTAIN THE DAVIS LIFT STATION AND NORTON EAST
RANCH OUTFALL SEWER INTERCEPTOR PROJECT.
WHEREAS,the City Commission did, on the I"day of June 2015, adopt the Bozeman
Wastewater Collection Facilities Plan Update which contains recommendations for the
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construction of the Davis Lane Lift Station and Norton East Ranch Outfall Sewer Interceptor; and
WHEREAS,the City Commission has adopted a Wastewater Impact Fee Fund Capital
Improvement Plan(CIP), which includes and authorizes the design and construction of the Davis
Lane Lift Station and Norton East Ranch Outfall Sewer Interceptor Projects; and
WHEREAS, the City Commission did, on the 2"a day of February, 2019, approve a
Professional Services Agreement with HDR Engineering to complete the design of the above
referenced project including the preparation of a Preliminary Engineering Report(PER); and
WHEREAS, City Engineering staff has reviewed and approved the PER, the preferred
alternative of which is in accordance with the previously approved Wastewater Collection
Facilities Plan Update and Wastewater Impact Fee CIP.
NOW, THEREFORE, BE IT RESOLVED by the City Commission of the City of
Bozeman,Montana,that it accepts the preferred alternative included in the PER for the Davis Lane
Lift Station and Norton East Ranch Outfall Sewer Interceptor Project and further that it has the
necessary legal,financial,institutional and managerial resources to construct,operate and maintain
the same.
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Resolution No.5112,Accept PER and Resource Statement for Davis Lift and Norton Interceptor Project
PASSED, ADOPTED, AND APPROVED by the City Commission of the City of
Bozeman,Montana, at a regular session thereof held on the 3rd day of February, 2020.
S MEHL
Mayor
ATTEST: ����
MIKE MAAS
Interim City Clerk
b lot
4 0. Mo
4*44�t VED AS TO FORM:
G SULLIVAN
Ci Attorney
2 of 2
FN
Davis Lane Lift Station
and Norton Ranch Sewer
Preliminary Engineering Report
Bozeman, MT
June 24, 2019
Contents
ExecutiveSummary......................................................................................................................7
1. Project Planning...................................................................................................................10
1.1 Location........................................................................................................................10
1.2 Environmental Resources Present...............................................................................11
1.3 Population Trends ........................................................................................................12
1.4 Community Engagement..............................................................................................12
2. Existing Facilities.................................................................................................................13
2.1 Location Map................................................................................................................13
2.2 History ..........................................................................................................................14
2.3 Condition of Existing Facilities......................................................................................14
2.4 Financial Status of any Existing Facilities.....................................................................14
2.5 Water/Energy/Waste Audits .........................................................................................14
3. Need for Project...................................................................................................................15
3.1 Health, Sanitation, and Security...................................................................................15
3.2 Aging Infrastructure......................................................................................................15
3.3 Reasonable Growth......................................................................................................15
4. Wastewater Collection Alternatives Considered..................................................................16
4.1 Lift Station and Force Main Alternatives.......................................................................16
4.1.1 Lift Station and Force Main Description ................................................................16
4.1.2 Lift Station and Force Main Design Criteria...........................................................16
4.1.3 Map .......................................................................................................................20
4.1.4 Environmental Impacts..........................................................................................20
4.1.5 Land Requirements...............................................................................................20
4.1.6 Potential Construction Problems...........................................................................20
4.1.7 Sustainability Considerations................................................................................20
4.1.8 Cost Estimates......................................................................................................21
4.2 Norton Ranch Gravity Sewer Alternatives....................................................................21
4.2.1 Norton Ranch Gravity Sewer Description..............................................................21
4.2.2 Norton Ranch Design Criteria ...............................................................................21
4.2.3 Map .......................................................................................................................23
4.2.4 Environmental Impacts..........................................................................................24
4.2.5 Land Requirements...............................................................................................24
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4.2.6 Potential Construction Problems...........................................................................24
4.2.7 Sustainability Considerations ................................................................................24
4.2.8 Cost Estimates ......................................................................................................24
5. Selection of Alternatives......................................................................................................25
5.1 Force Main....................................................................................................................25
5.2 Lift Station Pumping .....................................................................................................26
5.3 Wetwell Design.............................................................................................................30
5.4 Lift Station Location/Interstate Bore .............................................................................31
5.5 Norton East Ranch Sewer............................................................................................32
6. Proposed Project.................................................................................................................34
6.1 Preliminary Project Design ...........................................................................................34
6.2 Project Schedule ..........................................................................................................35
6.3 Permit Requirements....................................................................................................36
6.4 Total Project Cost Estimate..........................................................................................37
6.5 Annual Operating Budget.............................................................................................37
7. Conclusions and Recommendations...................................................................................39
AppendixA..................................................................................................................................40
PreliminaryOPCC ..............................................................................................................40
AppendixB..................................................................................................................................41
SRF Environmental Requirements for PER Submittal.........................................................41
Table 1. Expected Initial Flows.....................................................................................................7
Table 2. Expected Flows over Lifespan of Lift Station..................................................................7
Table 4-1. Expected Initial Flows................................................................................................17
Table 4-2. Expected Flows over Lifespan of the Lift Station.......................................................17
Table 4-3. Norton East Ranch Sewer Main Pipe Sizes ..............................................................23
Table 5-1. Expected Pipe Velocities ...........................................................................................25
Table 5-2. Expected Force Main Residence Times....................................................................26
Table 5-3. Flows Delivered by Pumping Arrangements......... ....................................................30
Table 6-1. Total OPCC for Project..............................................................................................37
Table 6-2. Expected Annual Operating Budget..........................................................................37
Figure1. Map of Project Area.......................................................................................................9
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Figure 2. Map of Gravity Sewer Route..........................................................................................9
Figure1-1. Map of Project Area..................................................................................................10
Figure 1-2. Project Area Wetland Delineation.............................................................................11
Figure 2-1. Map of Project Area and WRF..................................................................................13
Figure 4-1. Map of Project Area..................................................................................................20
Figure 4-2. Map of Norton Sewer Outfall Route..........................................................................23
Figure 5-1. Operating Point with One Jockey Pump & One Force Main in Operation................27
Figure 5-2. Operating Point with One Duty Pump & One Force Main in Operation....................28
Figure 5-3. Operating Point with Two Duty Pumps & One Force Main in Operation..................28
Figure 5-4. Operating Point with Two Duty Pumps & Two Force Mains in Operation ................29
Figure 5-5. Operating Point with Three Duty Pumps & Two Force Mains in Operation..............29
Figure 5-6. Operating Point with Four Duty Pumps & Two Force Mains in Operation................30
Figure 5-7. Proposed Wetwell Design ........................................................................................31
Figure 6-1. Lift Station and Wetwell Preliminary Design.............................................................34
Figure 6-2. Proposed Wetwell Design ........................................................................................35
Figure 6-3. Proposed Project Schedule......................................................................................36
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City of Bozeman
Davis Lane and Norton Ranch Sewer
Preliminary Engineering Report
Prepared By:
Coralynn Revis, PE
HDR
(406) 532-2219
CORALYNN L.
REVI
Nu. l i^►'
SS�ON/\\-
I hereby certify that this document was prepared by me or under my direct supervision, and that
I am a duly registered Engineer under the laws of the State of Montana.
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Executive Summary
The Davis Lane Lift Station and Norton Ranch Sewer will be a major addition to the City of
Bozeman's wastewater collection system. The project includes the construction of the Norton
East Ranch Outfall Sewer, a new lift station and wetwell, and a force main from the lift station to
the City of Bozeman Water Reclamation Facility. The project's infrastructure will primarily
service the northwest portion of the City.
Growth in Bozeman is the driving force behind the need for this project. The City of Bozeman,
particularly areas in the northwest part of Bozeman, have been and will continue to experience
rapid growth. Additionally, northwest Bozeman is also the proposed site for the new Bozeman
high school and the Billings Clinic, both of which will be the sources of significant wastewater
flows into Bozeman's collection system.
As this project is meant to serve a growing population, the lift station, and its associated
components, must be capable of handling a wide range of flows. Flows are expected to
increase substantially over the lifespan of the project, which presents a unique design
challenge. Table 1 shows the range of expected flows at lift station startup, and Table 2 shows
the range of expected flows over the lifespan of the project.
Table 1. Expected Initial Flows
. Average D- Design Flow
Norton Ranch Phase 1-5 71 218
New High School Flows 9 53
Hospital Flow 179 602
Total 259 873
Table 2.Expected Flows over Lifespan of Lift Station
Average Design Flow Rate Peak Design Flow Rate Lane Lift Station Startup 71 218
Start Up after Billings Clinic Connection 259 873
Norton East Ranch Interceptor Connected 2,570 4,800
Gooch Hill LS and Hidden Valley LS connected
to Davis Lane LS 5,625 10,400
A number of alternatives pertaining to the project design were explored. Several wetwell
alternatives were evaluated, including a traditional versus self-cleaning style and a single versus
dual wetwell arrangement. A single self-cleaning style wetwell was ultimately selected due to its
simplicity, reduced maintenance requirements, and cost-effectiveness.
A number of wetwell pumping arrangements were also considered, including the installation of
four larger pumps requiring no replacement with increasing flows, the installation of four smaller
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pumps that would require complete replacement once flows increased, and the installation of a
mix of smaller pumps and larger pumps that could handle the full range of expected flows.
The evaluation resulted in a recommendation to install a total of five pumps; four operational
pumps and one standby pump. All pumps will be submersible style pumps. However, during the
initial startup flows, only three pumps will be installed in the wetwell; one smaller"jockey" pump
and two duty pumps. The jockey pump would be capable of pumping a range of flows from
roughly 500 gpm to 2,000 gpm at 30 feet of head. The duty pump would be capable of pumping
a higher flow rate of roughly 3,000 gpm at 70 feet of head. Once the initial wetwell flows
exceeded the jockey pump's likely upper pumping threshold of 2,000 gpm, the jockey pump
would be replaced with an additional duty submersible pump. Once flows to the wetwell
increase above 3,500 gpm, two additional duty pumps would be installed, which would bring the
total number of pumps installed in the wetwell to five. One of these duty pumps would be a
backup pump and would not operate regularly.
Several alternatives pertaining to the lift station location and force main arrangement were
considered. Many force main arrangements were evaluated, including a singular force main,
dual force mains of identical size, and dual force mains of differing size. A dual 18 inch force
main arrangement was ultimately selected, as it best conveyed the expected flow rates at
adequate velocities. The possibility of locating the lift station south of 1-90, so as to minimize the
size of the interstate bore, was explored extensively. However, property owners in the area
were ultimately unsupportive of such an action, and existing right of ways constrained available
space. Consequently, the lift station will be placed on the north side of the highway on City
property and the boring under the interstate will be sized for the gravity sewer.
Several alternatives pertaining to the Norton East Ranch Sewer route were evaluated. The
selected sewer gravity main alternative will begin at Baxter Lane, just west of Flanders Mill
Road, and end at the proposed lift station. This route is consistent with the sewer route
previously outlined in Alternative 1A in the Bozeman Wastewater Collection System—Technical
Memorandum: Norton East Ranch Sewer Outfall Alternatives Evaluation (DOWL, November
2018). Design considerations will be made to reduce the sewer depths at Cattail Street and
Davis Lane identified in the DOWL memo in order to improve the constructability of the gravity
sewer.
A map showing the location of the lift station can be seen in Figure 1, and a map of the gravity
sewer route can be seen in Figure 2.
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Figure 1.Map of Project Area
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Figure 2.Map of Gravity Sewer Route
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1 . Project Planning
11 „`!! Location
The various components of the Davis Lane Lift Station and Norton Ranch Sewer project
(hereinafter referred to as 'the project') will be constructed in the NW portion of the City of
Bozeman. The Davis Lane Lift Station will generally be located near Interstate 90, with an
accompanying force main routed to the City of Bozeman Water Reclamation Facility (WRF). A
map of the project area can be seen in Figure 1-1.
The Norton East Ranch Sewer outfall will intercept gravity sewer flows from the existing 27-inch
sanitary sewer main in Baxter Lane just west of Flanders Mill Road. The new sewer main will
generally be routed through open space within Baxter Meadows Subdivision, then cross
Bozeman Elementary District No. 7 property and run along the north side of Cattail Street. The
sewer main will be routed to the north along Davis Lane and cross East Valley Center Drive,
Interstate 90, and the 1-90 Frontage Road to the proposed lift station. A map of the Norton East
Ranch sewer outfall alignment can also be seen in Figure 1-1.
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Figure 1-1. Map of Project Area
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1.2 Environmental Resources Present
The proposed project is anticipated to require water quality permits due to the presence of
wetlands and other water bodies within the study area. To facilitate anticipated permitting
requirements, a field investigation was completed on May 28 to 29, 2019 for the 33.5 acre study
area that included wetland and stream identification, delineation, and classification. A total of
1.03 acres of wetlands and 0.19 acres of streams were delineated within the study area. An
overview of the results of the delineation are shown in Figure 1-2.
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rri Study Area �\
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Figure 1-2. Project Area Wetland Delineation
Development of a full wetland and stream delineation report is underway, the results of which
will be incorporated into the design documents for the proposed project.
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Population Trends
The City of Bozeman is currently experiencing rapid growth, particularly in the northwest portion
of the City where the project will be constructed. Bozeman has a current population of 46,596
people according to the most recent population estimate from the US Census Bureau, dated
July 2017. This represents a 25.0% increase in population since 2010, or roughly 3.6% growth
per year. In recent years, the growth rate in Bozeman and the surrounding Gallatin Valley has
ranked among the highest in the nation and there is little indication that growth rates will slow in
the coming years.
1.4 Community Engagement
The City of Bozeman Wastewater Collection System Facility Plan (2015) outlined the plan for
future service to the areas west of the City and included the plan for the Davis Lane Lift Station
and the Norton East Ranch Sewer. The facility plan was a public process and presented to the
Commission. Further, the Capital Improvement Plan process is public and included this project.
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2. Existing Facilities
Existing facilities relevant to this project are the City of Bozeman Water Reclamation Facility
(WRF), the existing 27-inch sanitary sewer main in Baxter Lane at the connection point, and the
existing 30-inch sanitary sewer main in Springhill Road at the connection point of the force
main. All other components pertaining to this project are to be constructed and do not currently
exist.
;).A Location Map
A map showing the location of the WRF in relation to the project can be seen in Figure 2-1.
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NORTH,
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Bozeman WRF
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Figure 2-1. Map of Project Area and WRF
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2.2 History
The City of Bozeman WRF is a cold weather biological nutrient removal plant that utilizes a 5-
Stage Bardenpho process. It was last upgraded in 2011. The average daily design flow for the
WRF is 8.5 MGD; it currently operates at approximately 6 MGD.
2.3 Condition of Existing Facilities
Currently, the Bozeman WRF has an average daily influent flow of 6 MGD. The WRF was
designed for an 8.5 MGD average daily flow, leaving room for roughly 2.5 MGD in additional
capacity before the plant will need to be upgraded. The secondary treatment processes at the
WRF are all designed for 10.6 MGD, which is the current maximum month flow. The hydraulic
components are sized for 19 to 25 MGD to pass peak day and peak hour flows.
The Davis Lane Lift Station is expected to provide an average of 8 MGD of additional flow at
build-out, far greater than the 2.5 MGD of additional available treatment capacity at the WRF.
Consequently, the WRF will need to be upgraded at some point during the lifespan of the Davis
Lane Lift Station.
The full build-out flows from the Norton East Ranch Interceptor will likely eclipse the capacity of
the WRF. At build-out, the Norton Ranch Interceptor will increase the lift station flows to an
average of 3.7 MGD and a peak of 6.9 MGD. Assuming that three to five percent of the total
anticipated flow from the Norton Interceptor is added per year, the capacity of the WRF would
likely be exceeded sometime in the early to mid-2030's. However, this estimate only considers
flows from Davis Lane, and does not include potential flows from elsewhere in the City.
2.4 Financial Status of any Existing Facilities
This is not applicable to this project.
2.5 Water/EnergyMlaste Audits
This is not applicable to this project.
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3. Need for Project
3.1 Health, Sanitation, and Security
The Davis Lane Lift Station and Norton East Ranch Sewer will provide the wastewater
infrastructure necessary to service the expanding population of this segment of the City.
3.2 Aging Infrastructure
The project consists of constructing entirely new infrastructure. As such, this section is not
applicable.
3.3 Reasonable Growth
The City of Bozeman is currently experiencing rapid growth. Consequently, several portions of
the City's wastewater collection system are at risk of becoming deficient as the population
increases. Much of the northwest portion of the City falls into this category. This area of the City
is also the planned site for a new high school and a new medical facility, the Billings Clinic, both
of which will be sources of large flows into the City's wastewater collection system. It will be
necessary to upgrade the wastewater infrastructure in this portion of the City before these new
connections come on line.
A number of infrastructure improvements that would address deficiencies in the City's collection
system were identified in the 2015 City of Bozeman Wastewater Collection Facilities Plan
Update. In regards to the northwest portion of the City, it was recommended that the Davis Lane
Lift Station and a force main from the lift station to the Bozeman WRF be constructed. It was
recommended in the report that the lift station be constructed so as to accommodate additional
flows once more connections came on line in the future.
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4. Wastewater Collection Alternatives Considered
4.1 Lift Station and Force Main Alternatives
Alternatives pertaining to the force main and the lift station design will be addressed in this
section. Alternatives pertaining to the lift station that require evaluation include the siting location
of the lift station, the configuration and type of wetwell, and the wetwell pumping arrangement.
Alternatives pertaining to the design of the force main include the pipe size and the number of
force mains. A"do nothing" alternative, in which no collection alternatives are constructed, was
considered along with the various alternative analyses presented below; however, this option
does not address the issues associated with growth within the service area and therefore will
not be carried forward for further evaluation.
4.1.1 Lift Station and Force Main Description
The lift station will consist of a pump building and a wetwell. The building will house equipment
and electrical components, and the pumps will be located in the wetwell. The force main will
extend from the lift station to the WRF, and will be located entirely on City property.
4.1.2 Lift Station and Force Main Design Criteria
The first step in the alternative analysis for the Davis Lane Lift Station, and associated force
main, will be to establish design criteria including the range of flows that the lift station will be
expected to handle. It is expected that the initial flows at startup will be quite small in
comparison to those that may be encountered once the Norton East Ranch Sewer system, and
all other accompanying collection points, are connected to the lift station. Consequently, the lift
station must be designed to handle both the initial startup flows and the expected future flows.
Pump selection and the sizing of the force main from the lift station to the WRF will be impacted
by these varying flow rates.
The lift station pumps can be sized for the initial influent flows, and be replaced as their capacity
is exceeded, or additional pumps can be installed once the original pumps can no longer meet
demand. The merits of replacing the lift station pumps as influent flows increase versus
installing additional pumps to meet increased flows will be evaluated.
The sizing of the force main will also be impacted by the wide range of expected influent flows.
It may be difficult to size a single force main that will adequately serve the full range of flows,
and it may be necessary to utilize a dual force main design. Consequently, the merits and
feasibility of utilizing a single versus dual force main design will be evaluated.
Another key design consideration will be the location of the lift station. The lift station could be
constructed north or south of 1-90, which will significantly impact the size of the interstate sewer
bore. If the lift station is located north of 1-90, the interstate sewer boring will connect the Norton
East Ranch Sewer Outfall, and other service areas south of 1-90, to the Davis Lane Lift Station.
Placing the lift station north of 1-90 would require a large bore to house the gravity sewer. If the
lift station were to be located south of 1-90, the interstate boring would require a smaller bore to
house the force main(s). While it would be advantageous to drill a smaller bore under the
interstate, it may not be possible to locate the lift station south of 1-90 due to right of way
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limitations and limited available property. The merits and feasibility of locating the lift station
north and south of 1-90 will be evaluated.
4.1.2.1 DESIGN FLOWS
Table 4-1 shows a summary of the near-term flows anticipated at the lift station. The following
assumptions were used to develop the near-term flows:
• Norton Ranch flows are based on 65 gallons per capita per day, with 2.17 people per
dwelling unit per the 2015 City of Bozeman Wastewater Collection Facilities Plan Update
and data from the 2010 US Census
• B-2 zoning was assumed for the hospital development as well as adjacent properties
contributing to the Davis Lane Lift Station
• B-2 zoning was assumed to generate 2,000 gallons per acre in the 2015 City of
Bozeman Wastewater Collection Facilities Plan Update
• The high school average and peak flows were based on a technical memo developed by
TD&H Engineering
Table 4-1.Expected Initial Flows
Average D• Design Flow Rate Ranch Phase 1-5 71 218
New High School Flows 9 53
Hospital Flow 179 602
Total 259 873
Most of the flow for the lift station will come from additional developments south of the existing
City boundary. Significant increases in lift station flows are anticipated when the Norton Ranch
Interceptor is connected to the Davis Lane Lift Station, and when the Gooch Hill and Hidden
Valley Lift Stations are connected to the Davis Lane Lift Station. Table 4-2 shows a summary of
the cumulative flows expected over the lifespan of the Davis Lane Lift Station.
Table 4-2. Expected Flows over Lifespan of the Lift Station
AverageCondition Design Flow Rate Peak Hourly Design Flow Lane Lift Station Startup 71 218
Start Up after Billings Clinic Connection 259 873
Norton East Ranch Interceptor Connected 2,570 4,800
Gooch Hill LS and Hidden Valley LS connected 5,625 10,400
to Davis Lane LS
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4.1.2.2 LIFT STATION SITING OPTIONS
The location of the lift station, either north or south of 1-90, will significantly affect the size and
shape of the interstate boring. If the lift station is located north of 1-90, then the interstate boring
will connect the Norton East Ranch Sewer Outfall, and other service areas south of 1-90, to the
Davis Lane Lift Station. If the lift station is located south of 1-90, then the interstate boring would
enclose the force main piping rather than the gravity sewer. In that scenario, the boring could be
made much smaller than if it needed to enclose the gravity sewer line.
The possibility of locating the lift station on the south side of the interstate within the Montana
Department of Transportation (MDT) right of way was explored extensively. However, MDT was
ultimately unsupportive of such an action, which effectively ended any consideration of placing
the lift station south of 1-90. Consequently, the lift station will be placed on the north side of the
highway, on City property, and the boring under the interstate will be have to be sized to
accommodate the gravity sewer.
4.1.2.3 FORCE MAIN CONFIGURATION AND SIZE
The target velocity through the force main piping is two to seven feet per second in order to
prevent the deposition of solids or create excessive headloss. Consequently, pipe velocity, and
the related headloss and solids settling, is the limiting factor in the design of the force main.
Maintaining a minimum force main velocity of two feet per second will be the key factor during
the initial lift station startup when flows are low, and maintaining a maximum force main velocity
below seven feet per second will be the key factor once all associated flows come on line.
Three potential force main arrangements were evaluated. A single force main could be used,
dual force mains of identical pipe size could be used, or dual force mains of differing size could
be used.
It is unlikely that a single force main arrangement would be able to adequately convey the wide
range of expected flows. If a single force main were to be used, then the pipe velocities
experienced during either the startup flows or the build out flows would inevitably vary drastically
from the necessary velocity range of two to seven feet per second. The force main would either
be too large or too small for one end of the flow range, and would not function as desired. If dual
force mains of differing size were used, then redundancy would be lost as the force mains would
no longer be identical to one another. As a result, the alternative consisting of dual force mains
will be utilized.
4.1.2.4 LIFT STATION PUMP CONFIGURATION OPTIONS
The lift station pumps must be capable of handling the entire range of flows outlined in the
design criteria. To do so, the pumps could be sized for the initial flows and then be replaced
entirely once their capacity has been exceeded, the pumps could be sized for the initial flows
and remain in operation once their capacity has been exceeded, and an additional pump(s)
could be installed to provide the necessary pumping capacity, or a combination of these two
approaches could be used in which a mix of pump models could be installed and replaced as
needed.
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The pumps could also be equipped with VFDs to allow for operation at a wider range of flows
within. The installation of VFDs would increase the capital cost, but would provide greater
operational ability and likely long-term energy savings.
Several pump types could theoretically be used for the project. However, given the likely
hydraulic conditions of the wetwell, submersible pumps will be best suited for use. The use of
submersible equipment will simplify installation and avoid equipment crowding in the pump
station.
4.1.2.5 LIFT STATION VVETWELL CONFIGURATION OPTIONS
The wetwell, and other features that cannot be easily changed in the future, will be sized for the
ultimate peak design flow of 15 MGD. There are several wetwell types and configurations that
could be used. A traditional wetwell design or a self-cleaning wetwell design could be selected,
and a singular or dual wetwell arrangement could be selected.
Traditional wetwell design is often focused on providing as much storage capacity as possible.
Consequently, wetwells of this sort are often deep, which can lead to cascading influent flow
and poor pump inlet hydraulics. When the influent flow is allowed to cascade freely into a deep
wetwell, it can cause vibration damage to bearings and shaft seals, and it can increase odor
release and corrosion. Air entrainment can also result from cascading influent, which can
reduce the capacity of the wetwell pumps.
An alternative to the traditional wetwell design is a self-cleaning style wetwell. Such a wetwell
has less storage than a traditional wetwell, but offers a number of design advantages. In
addition, the issues surrounding the reduced storage volume can be offset by the use of VFDs.
The self-cleaning style design incorporates the use of an inlet ramp and pump trench with
suction bells. The inlet ramp and pump trench layout provides for mechanical cleaning of the
wet well by making use of pump hydraulics. Low water level is kept at the invert of the inlet pipe
to minimize air entrainment and reduce the potential for differential velocities. The wet well
working levels operate between the crown and invert of the influent pipe.
The pumps are arranged inline to facilitate the self-cleaning nature of the wet well. The wet well
section is sized such that flow velocity across the pump inlet is kept below four feet per second
to maintain proper inlet hydraulics. The pump inlets are located in a trench much lower than the
water level providing for almost quiescent flow conditions. This improves pump intake hydraulics
and minimizes cavitation.
The self-cleaning wetwell is designed with 60 degree trench side slopes to prevent the
accumulation of settleable solids, eliminate the free fall of influent, and reduce scum buildup.
Odors are significantly reduced by eliminating the cascading effect typical of traditional small
wetwell designs.
Due to the wide range of flows expected over the lifespan of the lift station, the possibility of
utilizing a dual wetwell design should be considered. Utilizing two smaller wetwells, as
compared to one larger wetwell, would allow for better hydraulics and pump sizing for the initial
startup phase of the lift station. The second wetwell could be activated when influent flows
19
increased. The primary advantage of such a design would be to optimize lift station
performance, particularly in the early stages of use.
4.1.3 Map
A map of the project area can be seen in Figure 4-1.
r� tl
..s
PRE EEO PROPOSED LIFT _
CAn55lN. STATION ON CITY OF _I
BOZEMAN PROPERTY
PROPOSEu
INTERMEDIATE
BORE ACCESS TIT
i tea`y`
� PROPOSED
FOATIEAIN
ROU
itGcu-c c.r � wERARaa
C OF
'GTfAlt C4FFx \� FORGTRdiN I'
13OZEMAN
FUTURE SEWER NIL'N \ - DTP
EMNSION IN DAYIS .
LANE
_ FROPO5E6 CONNECTION
30'SEWER y _.
JTFALL TO WWTP I,
NORM • \
Figure 4-1. Map of Project Area
4.1.4 Environmental Impacts
The Davis Lane Lift Station will be constructed on the existing WRF property owned by the City.
There are no anticipated environmental impacts stemming from lift station construction activities
in this area.
4.1.6 Land Requirements
The project will consist of a wetwell and the associated lift station building. The preliminary
building footprint is 65 feet by 30 feet. The preliminary wetwell footprint is approximately 14 feet
by 40 feet. The two structures will be located in close proximity to one another.
4.1.6 Potential Construction Problems
No potential construction problems have been identified during the preliminary design phase.
4.1.7 Sustainability Considerations
Each of the pumps could be sized and fitted with a variable frequency drive (VFD) that would
allow each pump to be operated at a variety of flow rates to match changing conditions.
Operating the pumps with VFDs would reduce energy consumption and optimize system
20
performance as well as mitigate any potential issues as a result of small storage availability by
using a self-cleaning wet well.
4.1.8 Cost Estimates
An opinion of probable construction cost (OPCC) for the lift station and force main was
completed based upon the preliminary project plans. The OPCC for the lift station building and
wetwell amounted to approximately $2.95 million. The OPCC for the force main amounted to
approximately $1.26 million. A more detailed cost estimate for these project components can be
seen in Appendix A.
4.2 Norton Ranch Gravity Sewer Alternatives
The sizing of the gravity main will be impacted by the expected flows, alignment options, and
existing topography of the alignment options.
The optimal route from the Baxter Lane connection point to the 1-90 crossing will be evaluated
based on availability of right-of-way, existing facilities, and future roadway expansion. Existing
topography also presents a design challenge.
Sewer main depths will be minimized when possible to avoid depths greater than 20 feet by
sizing a gravity main at minimum slopes based on the expected peak flows and a design flow
depth to pipe diameter ratio (d/D) of 0.75. A variety of pipe sizes will be considered to take
advantage of steeper existing topography near the connection point and 1-90 crossing
4.2.1 Norton Ranch Gravity Sewer Description
The Norton East Ranch Sewer system will connect to the existing 27-inch sanitary sewer main
in Baxter Lane,just west of Flanders Mill Road, and convey flows to the Davis Lane Lift Station.
4.2.2 Norton Ranch Design Criteria
Design criteria for the gravity sewer main include a design flow depth to pipe diameter ratio of
0.75 based on a Manning's "n" value of 0.013, minimum pipe slopes as outlined in Circular
DEQ-2, manhole spacing in accordance with City of Bozeman design standards, a 0.1-foot drop
between inverts at manholes, and a minimum depth of cover of 4 feet. The City of Bozeman
usually requires a 0.2-foot drop between inverts at manholes, however the City has approved
the smaller drop to limit sewer depths.
The target flow depth to sanitary sewer main diameter (d/D) ratio is 0.75, with a minimum
flowing full velocity of 2.0 feet per second. Minimum slopes for the gravity sewer pipes have
been evaluated in accordance with Circular DEQ-2: Design Standards for Public Sewage
Systems.
4.2.2.1 DESIGN FLOW
A peak design flow of 6.9 MGD has been identified for the Norton East Ranch sewer main.
�.�.2.7 NORTON RANCH GRAVITY SEWER ROUTING OPTIONS
The route of the gravity sanitary sewer main has been extensively evaluated in prior engineering
reports. The proposed gravity main will begin at Baxter Lane just west of Flanders Mill Road and
21
end at the proposed lift station. Availability of right-of-way, existing utilities, and constructability
will dictate the proposed route from the known starting and ending points.
Sewer outfall alternatives were previously evaluated in the Bozeman Wastewater Collection
System —Technical Memorandum: Norton East Ranch Sewer Outfall Alternatives Evaluation
(DOWL, November 2018). The technical memorandum evaluated four options, listed and briefly
summarized below:
• Alternative 1A: Dedicated Norton East Sewer Outfall—This route includes a
dedicated sewer main north from Baxter Lane through Baxter Meadow Subdivision, east
along Cattail Street, and north on Davis Lane to 1-90. Limitations and constraints for this
option include unavailable right-of-way, topography constraints resulting in deep (30
feet) sewer installation, shallow groundwater, and construction through streams and
wetlands. The deepest section of the sewer route was identified at the corner of Cattail
Street and Davis Lane, where the sewer would be routed north towards the interstate.
Various options were explored to reduce the depth at this point.
• Alternative 1 B: Nearly Dedicated Norton East Outfall—This route would be similar to
Alternative 1A, with the exception of the beginning section (Baxter Lane to Cattail
Street). This alternative proposed a route north from Baxter Lane along Riata Road,
which would include the removal and replacement of an existing sewer main. This
alternative would avoid construction along an existing stream and wetland, and reduce
depth at the deepest section of the route by approximately five feet.
• Alternative 2: Baxter Meadows Lift Station #2 & 27th/Cattail Interceptor—This
option includes upgrading the existing Baxter Meadows Lift Station near Cattail Street,
prior to the deepest section of sewer identified in Alternative 1A. This alternative would
require a new force main to the intersection of Cattail Street and Davis Lane and
utilization of the existing sewer mains in place. This alternative would require upgrades
to existing sewer mains as well as a future 1-90 crossing, Davis Lane lift station, and
force main from the lift station to serve future developments.
• Alternative 3: Interim Improvements to Existing Collection System and Baxter
Meadows Lift Station —This alternative proposes the upgrading of existing facilities,
which would be required for Alternative 2 to occur. Alternative 3 would ultimately only be
implemented if Alternative 2 was selected as the long-term vision for the sewer system.
Additional details, including cost estimates, preliminary plan and profile sheets, and maps of the
various alternatives may be found in the technical memorandum. The City of Bozeman has
chosen to proceed with Alternative 1A, but the sewer will require a depth less than the 30 feet
identified in the technical memorandum. Design considerations to reduce the depth at Cattail
Street and Davis Lane have since occurred and are detailed in the following sections.
4.2.2.3 NORTON RANCH GRAVITY CONFIGURATION AND SIZE
Given the design flows listed in previous sections, a 33 inch diameter pipe at minimum slope
(0.052 feet per 100 feet)will convey the design flow at a 0.75 d/D ratio. Existing topography will
allow for pipes to be sloped steeper than the minimum grade in areas of the project. In these
areas, smaller pipe sizes have been evaluated to meet the target 0.75 d/D ratio. Additionally, 36
22
inch pipe has been considered in an area of the project where depth of the sewer main presents
a significant design challenge.
Design flows for the project, in conjunction with the design Manning's n value and minimum
slopes outlined in DEQ-2, will dictate the proposed pipe diameters. Various pipe sizes have
been considered to convey the flow and are summarized in Table 4-3 below.
Table 4-3. Norton East Ranch Sewer Main Pipe Sizes
Pipe Diameter(in) Minimum Slope Flow Depth (in)
27 0.15 19.9 0.74
30 0.085 22.2 0.74
33 0.052(minimum slope as listed in 24.6 0.75
DEQ-2)
36 0.046(minimum slope as listed in 22.6 0.63
DEQ-2)
4.2.3 Map
A map of the planned gravity sewer route can be seen in Figure 4-2.
g,.
- c � F,rertun WRF �
•s
1
t
l. N As
i
fig
Figure 4-2. Map of Norton Sewer Outfall Route
23
4.2.4 Environmental Impacts
The Norton East Ranch gravity sewer main will be installed near a number of ditches and
tributaries. From Baxter Lane to Kimberwicke Street, the gravity sewer pipe will be installed
adjacent to and cross the Maynard Border Ditch at the south end of the project. The alignment
will also cross a number of small tributary streams along Cattail Street. A portion of the sewer
main will be installed adjacent to a tributary stream at the south end of Davis Lane and will cross
Cattail Creek at the north end of Davis Lane. All stream crossings will be in accordance with
Circular DEQ-2 and a "Joint Application for Proposed Work in Montana's Streams, Wetlands,
Floodplains, and Other Water Bodies"will be submitted for the necessary stream permits. In
addition, wetlands have been delineated along the entire length of the project to quantify
impacts to existing jurisdictional wetlands. No other environmental impacts are anticipated.
4.2.6 Land Requirements
The gravity sewer main will be located within public right-of-way or easements for the entirety of
the route. There are several locations where additional easements are required. Generally, a
30-foot temporary construction easement and 30-foot permanent easement will be provided (60-
foot total) where existing right-of-way is not available.
4.2.6 Potential Construction Problems
There were several hurdles encountered during the preliminary design phase concerning
property easements and right of way use, constructability of sewer main given depths of the
main and available space, and risks involved with a large diameter bore given the site
conditions. These hurdles are discussed further in individual sections to which the subject is
pertinent.
4.2.7 Sustainability Considerations
The Norton East Ranch gravity sewer main has been sized to allow for the future development
of the full drainage basin. As such, construction improvements to upsize the sewer, based upon
future development, will not be needed. This design consideration will save resources and
reduce construction impacts to the area.
4.2.8 Cost Estimates
An OPCC was completed for the gravity sewer and the sewer interstate crossing, respectively,
based upon the preliminary project plans. The OPCC for the gravity sewer main from Baxter
Lane to 1-90 amounted to $4.8 million, and the OPCC for the gravity sewer crossing under 1-90,
the railroad tracks, and Frontage Road amounted to $3.9 million. The detailed cost estimates for
these project components are included in Appendix A.
24
5. Selection of Alternatives
5.1 Force Main
As mentioned previously, a dual force main arrangement of identical size was selected. Given
the wide range of flows expected between start up and build out, a dual force main design will
be necessary to adequately convey the flows at proper velocities. Using a dual force main will
allow one force main to be used when flows are low, and two to be used once flows to the lift
station increase. The force mains would serve as redundant pipelines to each other since they
will be the same diameter. A dual force main arrangement of differing size was not selected due
to the loss of redundancy that using differing diameters would entail, and because of the
increased hydraulic complexity that would result.
Dual force main configurations were evaluated for a number of pipe sizes. A dual force main
arrangement employing two 18 inch diameter force mains was ultimately selected. This
arrangement best fit the expected range of flows and the associated capacities of the selected
pumps. A summary of the expected pipe velocities at the various expected pumping
configurations is shown in Table 5-1.
Table 5-1. Expected Pipe Velocities
-Alm= Total Flow(gpm) Pipe Velocity(ft/s)
One Jockey Pump Operating on fill/draw, One 18" FM 1,600 2.02
One Jockey Pump Operating at 601-1z, One 18" FM 2,280 2.87
One Duty Pump, One 18" FM 3,890 4.90
Two Duty Pumps, One 18" FM 5,180 6.53
Two Duty Pumps, Two 18" FMs 7,780 4.90
Three Duty Pumps, Two 18" FMs 9,400 5.93
Four Duty Pumps, Two 18" FMs 10,360 6.53
The selected pipe diameter is well suited to the expected flow conditions. On the upper end of
the flow spectrum, the pipe velocity would peak at approximately 6.53 feet per second if the
build out flow conditions were to be reached and all four pumps were operational. On the lower
end of the flow spectrum, the initial startup flows would result in a pipe velocity below two feet
per second, but only if the jockey pump was operated continuously. To address this, the pump
would be operated on fill/draw to ensure the pipe velocity remained above two feet per second,
or as close to two feet per second as would be possible. This intermittent pumping will make it
possible to select a larger force main size and still maintain adequate pipe velocity at the
beginning of the lift station's operation. Once additional flows came on line the pumps would be
operated continuously.
Force main residence time was also considered for the array of expected flow conditions. Long
residence times can result in odor generation and corrosion in downstream facilities, and should
25
generally be avoided. A summary of the expected residence times at the various configurations
is shown in Table 5-2.
Table 5-2.Expected Force Main Residence Times
TotalConfiguration . . Residence
One Jockey Pump Operating on fill/draw, One 18" FM 1,600 0.504
One Jockey Pump Operating at 601-1z, One 18" FM 2,280 0.354
One Duty Pump, One 18" FM 3,890 0.207
Two Duty Pumps, One 18"FM 5,180 0.156
Two Duty Pumps,Two 18" FMs 7,780 0.104
Three Duty Pumps,Two 18"FMs 9,400 0.086
Four Duty Pumps,Two 18"FMs 10,360 0.078
The recommended maximum pipe residence time is generally no more than two hours. The
calculated residence times in the table above show that this should not be an issue for any of
the force main or pumping arrangements.
5.2 Lift Station Pumping
The pros and cons of the various pumping arrangements outlined in the alternatives evaluation
were considered. Ultimately, the evaluation resulted in a recommendation to install five pumps;
four operational pumps and one standby pump. All pumps will be submersible style pumps.
However, during the initial startup flows, only three pumps will be installed in the wetwell; one
smaller"jockey" pump and two duty pumps. The jockey pump would be capable of pumping a
range of flows from roughly 500 gpm to 2,000 gpm at 30 feet of head. The duty pump would be
capable of pumping a higher flow rate of roughly 3,000 gpm at 70 feet of head. Once the initial
wetwell flows exceeded the jockey pump's likely upper pumping threshold of 2,000 gpm, the
jockey pump would be replaced with an additional duty submersible pump. Once flows to the
wetwell increase above 3,500 gpm, two additional duty pumps would be installed, which would
bring the total number of pumps installed in the wetwell to five. One of these duty pumps would
be a backup pump and would not operate regularly.
The selected pumping arrangement will simplify the design of the wetwell, as completely
changing each installed pump model, once flows increased, would make it difficult to properly
size the dimensions of the wetwell. Replacing just one initial jockey pump will allow the wetwell
to be sized for the eventual duty pumps and still maintain adequate hydraulics. This pumping
arrangement also minimized the purchase of extraneous pumps without compromising wetwell
performance.
Additionally, all pumping equipment will be selected to enable lifting/removal of the equipment
from the deck level above the wetwells. The pumps will be installed with a guide rail and an
access door in the wetwell deck above each respective pump to allow for simple removal and
replacement.
26
All pumps will be equipped with a VFD. Equipping each pump with a VFD will allow each pump
to be optimized for the wide range of possible influent flows at any given time.
Pumps, valves, and all other metal components that will be submerged in or handle raw
wastewater in the pump stations will be fabricated from stainless steel or coated cast iron to
protect against corrosion and minimize maintenance requirements.
The following figures demonstrate the various operating points with one, two, three, and four
pumps in operation, and one or two force mains in operation. In each case, the operating points
shown are for the individual pumps, even when multiple are in operation. The blue pump curve
represents the 100% operating capacity of the pump, while the green pump curve represents
the pump capacity when turned down to 40Hz, the likely lowest turndown capability of the
pumps. A dual 18 inch diameter force main configuration was used to develop the system curve.
120 ----_-- ..__ .---`----- •--------- .. i
iio I E r I ! t =
-r r
--- i
x eo
= 80 ---------'-- --,-i-'I--- ------------ -------� �---------- --- ------'-'r—'--I 1--
t I v -
70 _ {_ __ _.__. .._�_._�__.t__ --_.__ -- --_.!_ __..__t_._-
vGo
I 7 I t I
1
40
--' r
0 r
--
I
- -
20 --' — _ ---•----•'---
i T-I
• I
0
0 5W 1,000 1,500 2,000 2.500 3,000 3.500 4.000 4,500 5.000
SINGLE PUMP FLOW(npm)
Figure 5-1.Operating Point with One Jockey Pump&One Force Main in Operation
27
zo - - - -- - --`------•-----
-----
i
ao - - ----- ---- ----- -- -- - ..... ---------
,
60 !40
G
t
J
f
•
20 .. ._ .- .---- --- - ---.._. -. .-..--- --- - -•------- ..... . ...... ...... ...
1 '
0 I
0 500 1,000 1.500 2,000 2.500 3,000 3,500 4.000 4,500 5,0C•')
SINGLE PUMP FLOW)gpm)
Figure 5-2. Operating Point with One Duty Pump&One Force Main in Operation
120 -.. --.. . .. - _. -. ._. .-- --_- - . . __ .........
110 -
--- -- -- --- ----
i
100 ------ --_ -------_---- ------ t ...... i --- - --
80 --t• - - - -
.. - - - - -- -- -- -i------ ------
= 70 - - - - - .. . .-- -----
U '
60 i - -
>. 50 -i - - - I - --! -- 1-------- -
o
40 !
' _- --------- _---_.__
I
20 .. -. .._. .. .- -----•--j -• ----- -•-------
10 _.. .-._ -...... ------........ ................. .... ---- ..-.-_.---
•
0 I .
0 500 1,OOD 1,500 2,000 2.500 3.000 3,500 4,000 4,500 5,000
SINGLE PUMP FLOW igpin)
Figure 5-3.Operating Point with Two Duty Pumps&One Force Main in Operation
28
120
110
100
go
I ,
= 70 J _ -
U '
60 . . _ _ _ ..._ _ _... j. .'-.. .. t .. ..
F40 -- - _ i --- _
O i
F 30 j 1
20 1
10
0 I
0 500 1.000 1,500 2,000 2.500 3,000 3,500 4.000 4,500 5,000
SINGLE PUMP FLOW(gpm)
Figure 6-4.Operating Point with Two Duty Pumps&Two Force Mains in Operation
120 _._ _____. -. _ — 1_ _
i
,00 — - Y _ i� !r --------
go L __i_i_ I. i - - ,�—
80
= 70 —
Q 60
o soI-
40
20
10
� t
0
0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4.500 5,000
SINGLE PUMP FLOW(gpm)
Figure 5-5.Operating Point with Three Duty Pumps&Two Force Mains in Operation
29
120 s -- — —--------— - --- ---•--------------- -- ----
I. j 1 . ..i i
00 --------—-----'-----------—t— ----- — — --, — — E — —
O ; I
x ,
� o ---- + I ..... � .: - '-go _ i. , ....... . .- . ......
--- -- - ----- ----- ... . -
I
40 -----i'—' ---•-- ---•------- `— ...i-- — ! t — +—
Q i -----------
~O t I I y
F ------- -------'----`--- --- '--`--'-- --- --
t
t'
0
0 500 1.000 1,500 2000 2500 3.000 3.500 4.000 4,500 5,000
SINGLE PUMP FLOW(0pm)
Figure 5-6.Operating Point with Four Duty Pumps&Two Force Mains in Operation
A summary of the range of flows that these configurations will be capable of delivering is shown
in Table 5-3. Pumps are assumed to be operating at full capacity unless indicated otherwise.
Table 5-3. Flows Delivered by Pumping Arrangements
Configuration Total Flow ..
One Jockey Pump Operating at 40Hz, One 18" FM 500
One Jockey Pump Operating at 60Hz, One 18"FM 2,280
One Duty Pump, One 18"FM 3,890
Two Duty Pumps, One 18" FM 5,180
Two Duty Pumps,Two 18" FMs 7,780
Three Duty Pumps,Two 18" FMs 9,400
Four Duty Pumps,Two 18"FMs 10,360
The range of flows that these various arrangements will be capable of delivering adequately
cover the expected range of influent flows to the Davis Lane Lift Station from initial startup to full
build-out conditions. Depending upon how quickly flows to the lift station increase due to
development connections, the pump(s) may operate on a fill/draw to maintain adequate velocity
in the force main.
5.3 Wetwell Design
A single, self-cleaning style wetwell was selected. The self-cleaning style was selected because
of the myriad benefits previously discussed, and the savings in annual maintenance fees that
would be realized by utilizing the self-cleaning style. Additionally, the slight decrease in available
storage that comes with a self-cleaning style wetwell will be partially offset by equipping the
wetwell pumps with VFDs. A section view of the proposed wetwell layout can be seen in Figure
5-7.
30
i
u u_
L
Figure 5-7.Proposed Wetwell Design
As can be seen in the wetwell arrangement shown in Figure 5-7, the pumps are arranged inline
to facilitate the self-cleaning nature of the wet well.
A dual wetwell design was not selected because it would increase construction costs for a small
increase in hydraulic performance. Roughly 30% to 50% more materials would likely be required
to construct a dual wetwell design as opposed to a singular wetwell. Additionally, a dual wetwell
would require the purchase of seven pumps, depending on pump selection, as opposed to the
six pump purchases required for a single wetwell. This would increase the relative cost of the
dual wetwell as compared to the singular wetwell design. Given the higher costs and increased
complexity of utilizing a dual wetwell design, it was determined that the performance benefits
were not great enough to warrant selection.
5.4 Lift Station Location/Interstate Bore
The location of the lift station north of 1-90 will require a bore of a casing pipe large enough to
convey a 30-inch gravity sewer carrier pipe under 1-90 and the Montana Rail Link (MRL) train
tracks. Additionally, grade control of the bore will be crucial, as the 30-inch sewer pipe will need
to convey a peak flow of 15 MGD by gravity. In addition to the gravity sewer bore, a 16-inch water
main will be bored, approximately 20-feet west of the gravity sewer bore, to serve future
development.
31
Various casing sizes for the two bores have been considered. The casing must be large enough
to contain the carrier pipe, accounting for pipe thickness and including bells at the pipe joints.
Typically, a 16-inch water main would be bored with a minimum 30-inch casing pipe. Considering
grade control will not be as crucial for the water main bore, a 30-inch casing pipe is proposed for
the water main bore. Casing pipe sizes ranging from 48-inch to 54-inch have been considered for
the gravity sewer main.A larger casing size has been considered more desirable for grade control,
as a larger casing would allow for minor grade adjustments to be made to the carrier pipe. Final
casing size is still being evaluated with the geotechnical engineer, MDT, and MRL.
Bore methods must also be evaluated for the 30-inch sewer main and 16-inch water main bores.
Several factors must be considered when evaluating bore methods. Critical site-specific factors
include the need for grade control, soil type, presence of groundwater, length of the bore, and
size of the casing pipe. As discussed above, the location of the lift station north of 1-90 requires a
bore method that will allow a 30-inch carrier pipe to gravity flow through the bore. Soils along the
bore path are expected to contain cobbles approximately 6-inch in diameter with occasional 12 to
18-inch boulders. Groundwater may be at an elevation higher than the top of the casing pipe,
depending on the time of year the construction occurs. The length of the bore will likely depend
on conclusions from ongoing discussions with the Montana Department of Transportation, but
could vary from 80 feet at the railroad tracks to 600 feet if it is required to bore across the entire
MDT and MRL right-of-way. Given the design constraints for the project, the two bore methods
that have been considered most feasible are pipe ramming and microtunneling.
Pipe ramming is often performed for bores with larger casing pipes. Pipe ramming allows for
bores to be completed in cobbles, as the cobbles can be removed via the casing pipe, and is
generally an economical option. The disadvantage to pipe ramming pertains to the grade
control. The grade of the casing pipe is set at the entrance of the bore pit and potentially cannot
be adjusted if an obstruction is encountered. Microtunneling is also a method used for large
casing pipe bores. Microtunneling allows for grade adjustments throughout the length of the
bore, making it a well-suited method for installations that require a strict grade tolerance.
Disadvantages to microtunneling include installation in cobbles, as large obstructions may
present issues during construction, as well as cost. The two bore methods and site conditions
will need to be further explored prior to selecting the preferred bore method. Grade control
would appear to be the limiting factor, however further geotechnical exploration is planned to
gain understanding of the anticipated soils through the bore path.
5.5 Norton East Ranch Sewer
Existing topography is generally steeper than the minimum slopes outlined in Table 4-3 along
the route north from Baxter Lane. A pipe diameter of 27 inches is proposed for this section, as
no pipes will be sloped flatter than 0.15 percent. Beginning near the point in the route where the
main is directed east, existing topography flattens and rises to the east, culminating at the
intersection of Cattail Street and Davis Lane. A 36 inch diameter pipe sloped at minimum slope
is proposed for this section of the route in order to limit depth at Cattail Street and Davis Lane.
The increase in pipe size is necessary to keep the sewer at a constructible depth, given the
presence of high groundwater, cobble soils, and limited right-of-way availability. The sewer main
route continues north on Davis Lane until reaching 1-90. Existing topography begins to steepen
32
on Davis Lane, allowing for slopes greater than 0.15 percent. The proposed pipe diameter for
this section will be 27 inches.
A minimum four feet of cover will be achieved through the project. A small portion of the route,
located on the Chief Joseph Middle School property, will require the placement of fill to achieve
the minimum four feet of cover. This portion of the route has an existing gravel trail on the
surface, which becomes muddy and partially unusable during rain events and periods of high
groundwater. Placement of the fill will elevate the trail, alleviating the issue. Drainage will be
considered for this section of the project and all proposed grade changes to the gravel trail will
be approved by the Bozeman Elementary District No. 7.
The proposed sewer depth at Cattail Street and Davis Lane has been reduced to just under 19
feet by utilizing the 0.1 foot drop at manholes, 36 inch sewer main, and placement of fill within
the Chief Joseph Middle School property. The sewer main will be significantly more
constructible at a depth of 19 feet but will still be challenging. Additional options for decreasing
the depth of the sewer main at the Cattail Street and Davis Lane intersection are continuing to
be explored.
33
6. Proposed Project
I Preliminary Project Design
The preliminary project design consists of the following alternative selections:
• The lift station will be located on the north side of Interstate 90
• A total of five submersible pumps will be installed in the wetwell at build out. Initially,
three pumps will be installed to handle initial flows, 2 duty pumps and one jockey pump.
The jockey pump will be sized to handle minimum flows to the Lift Station. It will be
replaced with an additional duty pump once flows to the Lift Station increase.
• Dual 18 inch diameter force mains will be utilized
• The lift station wetwell will be a self-cleaning design
• The Norton East Ranch Sewer will consist of a gravity sanitary sewer main from Baxter
Lane to 1-90 via Baxter Meadow Subdivision, Cattail Street, and Davis Lane
These selections constitute the preferred alternatives for this project, and the City possesses
the necessary legal, financial, institutional, and managerial resources to construct, operate and
maintain the eventual facilities. An in depth discussion of the evaluation processes for these
alternative selections is included in Sections 4 and 5.
A plan view of the preliminary lift station and wetwell design can be seen in Figure 6-1.
i
i
I
Illf
901 IN
II
l
'Tl
Figure 6-1. Lift Station and Wetwell Preliminary Design
34
A section view of the proposed wetwell layout can be seen in Figure 6-2.
i
l
Figure 6-2. Proposed Wetwell Design
6.2 Project Schedule
The project schedule will allow the project to be completed and operational by the summer of
2020 to accommodate the opening of the City's new high school. Final design plans for the
project will be completed by August 2019 to allow for adequate construction time. The proposed
schedule of work can be seen in Figure 6-3.
35
v
' '' •�• •�• •Ir •fir •fir r�� •��
t ,
•�• ��� yea
Figure 6-3. Proposed Project Schedule
6.3 Permit Requirements
A permit will be required from the Montana Department of Transportation (MDT) and Montana
Rail Link (MRL) to bore the gravity sewer under 1-90 and the railroad tracks that parallel the
interstate. MDT and MRL are aware of the project and the plan to bore under the railroad tracks
and interstate.
The proposed project is also anticipated to require water quality permits due to the presence of
wetlands and other water bodies within the study area. Under the federal Clean Water Act
(CWA) Section 404, a permit is required for the discharge of dredged or fill material into waters
of the United States, which includes wetlands. Any construction occurring within the delineated
wetland and streams is anticipated to require the following permits and authorizations:
36
• CWA Section 404 Permit— U.S. Army Corps of Engineers (USACE)
• CWA Section 401 Certification — MT DEQ
• Montana Pollutant Discharge Elimination System (MPDES) General Permit— Montana
DEQ
• Short-Term Water Quality Standard for Turbidity (318 Authorization) — Montana DEQ
By federal law (Clean Water Act) and associated policy, it is necessary to avoid project impacts
to wetlands wherever practicable, minimize impacts where impact is not avoidable, and in some
cases mitigate for impacts where avoidance and minimization is not possible. If unavoidable
impacts are anticipated, a Joint Application for Proposed Work in Montana's Streams, Wetlands,
Floodplains, and Other Water Bodies permit application will be submitted to the appropriate
regulatory agencies to obtain the necessary authorizations prior to construction.
6.4 Total Project Cost Estimate
An OPCC was completed for each major project component. These cost estimates are
summarized in Table 6-1 below. A more detailed breakdown of the OPCC for each project
component can be seen in Appendix A.
Table 6-1.Total OPCC for Project
ComponentProject •-
Lift Station $2.95 Million
Force Main $1.26 Million
Gravity Sewer Main $4.81 Million
Sewer Interstate Crossing $3.93 Million
Total $13.0 Million
6.5 Annual Operating Budget
An opinion of the probable annual operating cost for the lift station can be seen in Table 6-2.
Table 6-2. Expected Annual Operating Budget
Parameterk
Pump Electricity Costs at Build Out $63,000.00
Additional Electricity Costs $12,000.00
Cleaning $5,000.00
Miscellaneous O&M Costs $20,000.00
Total $100,000.00
The electrical costs of running the wetwell pumps constitutes the majority of the anticipated
annual operating budget. The annual pump electrical cost of$63,000 shown in the table
represents the expected cost to pump the average daily design flow rate of 5,625 gpm for 24
hours a day. However, the annual electricity costs for the pumps would be far less during the
initial lift station startup period, as there would likely only be one pump in operation for several
37
hours a day. Electricity costs during the startup period for intermittently operating the jockey
pump would likely be in the range of$10,000 a year. As the hours of pump operation increase
and more pumps are brought online, the annual electricity costs will gradually rise to the
$63,000 range shown in Table 6-2.
There would likely be additional electrical costs relating to lift station operation, and some
various cleaning and maintenance costs. These annual costs are accounted for in Table 6-2.
38
7. Conclusions and Recommendations
The wide range of expected influent flows over the lifespan of the lift station, roughly 200 gpm to
10,400 gpm, presents a unique design challenge. It is difficult to properly size and design a lift
station that will be capable of servicing anywhere from a trickle to a torrent of influent flow, but
the preliminary alternatives selected in this PER should adequately meet the identified design
criteria.
The early stages of lift station operation will likely present the most challenging operating
conditions. Depending upon how quickly flow sources come on line, there may be a period
when the lift station pumps will need to be operated intermittently to maintain adequate pipe
velocity and pump hydraulics. This period of intermittent operation should be relatively short
lived, and the challenge will be alleviated once additional flows are connected.
The interstate sewer boring will be a large undertaking. Unfortunately, no approach was
determined that would've allowed the lift station to be placed south of 1-90. Placing the lift station
south of the interstate would have meant the boring could be made smaller, as it would only
need to house the force main rather than the large gravity sewer. With no available property
south of the interstate, the lift station will have to be placed north of 1-90 on City property.
The schedule for the project will be fairly exact to ensure that the lift station will be operational
before the new Bozeman high school opens in August of 2020. Final design plans for the project
will be completed by August 2019 to leave adequate construction time to meet this necessary
completion date.
39
Appendix A
Preliminary OPCC for Davis Lane Lift Station
and Norton Ranch Sewer Project Components
40
SANDERSON
STEWART E
14 Jun-19
Preliminary Engineer's Opinion of Probable Cost
For
Davis Lane Lift Station and Norton Sewer Project
Project Cost Summary
Opinion of Probable Cost Based on 30% Plans
Schedule 1,Subtotal Gravity Sewer Main from Baxter Lane to I-90 = $4,004,190.08
Schedule 2,Subtotal Tunnel Across I-90,Railroad Tracks,and Frontage Roads = $3,276,020.00
Schedule 3,Subtotal Davis Lane Lift Station Force Main = $1,048,300.00
Subtotal = $8,328,510.08
20% Contingency = $1,665,702.02
Total Opinion of Probable Cost = $9,994,212.10
All items are complete and in place.
-Based on 30%design as of June 14,2019.
-Engineering Design,Contract Administration,and right-of-way/easement aquisition are not included in this estimate.
-Sanderson Stewart cannot warrant that any opinions of probable cost provided by Sanderson Stewart will not vary
from actual costs incurred by the client. Sanderson Stewart has no control over the cost or availability of labor,
equipment,materials,or over market conditions or the Contractor's method of pricing. Sanderson Stewart makes no
warranty,express or implied,that the bids or the negotiated cost of the work will not vary from Sanderson Stewart's
opinion of probable cost.
SANDERSON (W,,
STEWART
6/14/2019
Engineer's Opinion of Probable Cost
For
Davis Lane Lift Station and Norton Sewer Project
ALL ITEMS ARE COMPLETE IN PLACE
Schedule 1-Gravity Sewer Main from Baxter Lane to I-90
ITEM EST.
Total C QTY. UNIT DESCRIPTION UNIT PRICE TOTAL PRICE
101 1 LS Mobilization and Insurance(10%) @ $364,017.28 /LS = $364,017.28
102 1 LS Traffic Control @ $50,000.00 /LS = $50,000.00
103 1 LS Stormwater Management and Erosion Control @ $20,000.00 /LS = $20,000.00
104 1 LS Groundwater Dewatering @ $350,000.00 /LS = $350,000.00
105 30 HR Exploratory Excavation(Large Crew) @ $600.00 /HR = $18,000.00
106 20 HR Exploratory Excavation(Small Crew) @ $300.00 /HR = $6,000.00
107 28 EA Underground Utility Crossing @ $500.00 /EA = $14,000.00
108 5,844 LF 27"PVC Sewer(6'-10'to Invert) @ $120.00 /LF = $701,300.40
109 1,173 LF 27"PVC Sewer(<10'-15'to Invert) @ $155.00 /LF = $181,770.05
110 378 LF 27"PVC Sewer(>15'to Invert) @ $200.00 /LF = $75,686.00
111 2,982 LF . 36"PVC Sewer(6'-10'to Invert) @ $180.00 /LF = $536,745.60
112 1,798 LF 36"PVC Sewer(<10'-15'to Invert) @ $215.00 /LF = $386,578.60
113 890 LF 36"PVC Sewer(>15'to Invert) @ $265.00 /LF = $235,903.00
114 20 EA 60"SS Manhole x 5'Depth @ $5,500.00 /EA = $110,000.00
115 81 __ VF 60"SS Manhole; Additional Depth @ $185.00 /VF = $14,962.80
116 1 EA New Manhole on Existing 27-inch Sewer Main @ $12,000.00 /EA = $12,000.00
117 15 EA 72"SS Manhole x 5'Depth @ $8,500.00 /EA = $127,500.00
118 88 VF 72"SS Manhole;Additional Depth @ $235.00 /VF = $20,593.05
119 3,970 LF Remove and Replace Curb and Gutter @ $35.00 /LF = $138,950.00
120 200 SF Remove and Replace Sidewalk @ $20.00 /SF = $4,000.00
121 1 LS Remove and Replace Irrigation Structure and Piping at Davis/Cattail @ $28,000.00 /LS = $28,000.00
122 9,142 SY Asphalt Restoration @ $35.00 /SY = $319,983.30
123 770 CY Imported Backfill to Achieve Minimum 4'Cover @ $35.00 /CY = $26,950.00
124 1 LS Wetlands Mitigation/Pemtitting(protective covenant area) @ $50,000.00 /LS = $50,000.00
125 1 LS Wetlands Mitigation/Permitting(other areas) @ $60,000.00 /LS = $60,000.00
126 1 LS Stream Crossing @ $20,000.00 /LS = $20,000.00
127 6.6 AC Vegetation Restoration @ $8,000.00 /AC = $52,800.00
128 5,230 SY Trail Restoration and Access Road @ $15.00 /SY = $78,450.00
Subtotal = $4,004,190.08
Subtotal w/20%Contingency = $4,805,028.10
SANDERSON (M,
STEWART
6/14/2019
Engineer's Opinion of Probable Cost
For
Davis Lane Lift Station and Norton Sewer Project
ALL ITEMS ARE COMPLETE IN PLACE
Schedule 2-Tunnel Across I-90,Railroad Tracks,and Frontage Roads
ITEM EST.
Total C QTY. UNIT DESCRIPTION UNIT PRICE TOTAL PRICE
101 1 LS Mobilization and Insurance(109/6) @ $297,820.00 /LS = $297,820.00
102 1 LS Traffic Control for Frontage Rd and E.Valley Shoulders @ $10,000.00 /LS = $10,000.00
103 1 LS Stormwater Management and Erosion Control @ $8,000.00 /LS = $8,000.00
104 1 LS Groundwater Dewatering @ $55,000.00 /LS = $55,000.00
105 40 IIR Montana Rail Link Flagger @ $150.00 /HR = $6,000.00
106 4 EA Underground Utility Crossing @ $1,500.00 /EA = $6,000.00
107 700 LF 48-inch Steel Casing Installed via Microtunneling @ $1,750.00 /LF = $1,225,000.00
108 1 LS 48-inch Casing Spacers and End Seals @ $40,000.00 /LS = $40,000.00
109 1 LS Cathodic Protection for 48-inch Steel Casing @ $25,000.00 /LS = $25,000.00
110 700 LF 30-inch Sewer Main in 48-inch Casing @ $165.00 /LF = $115,500.00
111 2 EA 72-inch Sanitary Sewer Manhole @ $8,500.00 /EA = $17,000.00
112 20 VF Extra Depth 72-inch Sanitary Sewer Manhole @ $235.00 /VF = $4,700.00
113 100 LF 36-Inch Sewer Main via Open Cut @ $280.00 /LF = $28,000.00
114 700 LF 48-inch Steel Casing Installed via Microtunneling @ $1,750.00 /LF = $1,225,000.00
115 1 LS 48-inch Casing Spacers and End Seals @ $40,000.00 /LS = $40,000.00
116 1 LS Cathodic Protection for 48-inch Steel Casing @ $25,000.00 /LS = $25,000.00
117 700 LF 16-inch Water Main in 48-inch Casing @ $100.00 /LF = $70,000.00
118 200 LF 16-inch Water Main via Open Cut @ $150.00 /LF = $30,000.00
119 1 EA Connect to Existing 8-inch Water Main @ $6,000.00 /EA = $6,000.00
120 2 EA New 16-inch Butterfly Valve @ $5,000.00 /EA = $10,000.00
121 2 EA New Fire Hydrant @ $5,500.00 /EA = $11,000.00
122 1 LS Seeding Restoration @ $8,000.00 /LS = $8,000.00
123 4 EA Ben tonite Trench Plug @ $2,000.00 /EA = $8,000.00
124 1 LS Ditch and Miscellaneous Surface Restoration @ $5,000.00 /LS = $5,000.00
Subtotal = $3,276,020.00
Subtotal w/20%Contingency = $3,931,224.00
SANDERSON (f
STEWART
6/14/2019
Engineer's Opinion of Probable Cost
For
Davis Lane Lift Station and Norton Sewer Project
ALL ITEMS ARE COMPLETE IN PLACE
Schedule 3,Davis Lane Lift Station Force Main
ITEM EST.
Total C QTY. UNIT DESCRIPTION UNIT PRICE TOTAL PRICE
101 1 LS Mobilization and Insurance(109/6) @ $95,300.00 /LS = $95,300.00
102 1 LS Traffic Control @ $10,000.00 /LS = $10,000.00
103 1 LS Stormwater Management and Erosion Control @ $7,500.00 /LS = $7,500.00
104 1 LS Groundwater Dewatering @ $20,000.00 /LS = $20,000.00
105 15 IiR Exploratory Excavation(Large Crew) @ $600.00 /HR = $9,000.00
106 10 HR Exploratory Excavation(Small Crew) @ $300.00 /HR = $3,000.00
107 12 EA Underground Utility Crossing @ $500.00 /EA = $6,000.00
108 3,800 LF - Dual 18"Force Main(Iwo pipes in one trench) @ $200.00 /LF = $760,000.00
109 1 LS Stream and Culvert Crossing @ $35,000.00 /LS = $35,000.00
110 1,700 SY Asphalt Restoration @ $35.00 /SY = $59,500.00
ill 3 AC Vegetation Restoration @ $6,000.00 /AC = $18,000.00
112 1 LS Fence Restoration @ $5,000.00 /LS = $5,000.00
113 1 EA Connection to Existing 30-inch Sanitary Sewer at WRF with New Doghouse
Manhole @ $20,000.00 /EA = $20,000.00
Subtotal = $1,048,300.00
Subtotal w/20%Contingency = $1,257,960.00
Davis Lane Lift Station and Wetwell Cost Estimate
Description Quantity Unit Base Unit Price Adjusted Price I-otal(S)
($/unit) ($/unit)
Division 1-General Requirements
General Requirements 1 LS $ 179.807.30 $ 179,807
Subtotal $ 179,807
Divison 3-Concrete
Pump Building Foundation Slab-on-Grade 50 CY $ 670 $ 33,500
Wetwell Slab on Grade 18 CY $ 670 $ 12.060
Wetwell Suspended Slab 14 CY $ 1,500 $ 20,556
Wetwell Concrete Walls 90 CY $ 1,200 $ 108,000
Wetwell Inlet Ramp 10 CY $ 1,200 $ 12,000
Wetwell Misc Concrete 351 CY 1 $ 1,200 $ 42,000
Subtotal $ 228,116
Divison 5-Metals
Pump Building Metal Roof 2000 SF $ 27 $ 54,000
Metal Framing 1 LS $ 30,000 $ 30,000
Trusses 1 LS $ 17,500 $ 17,500
Subtotal $ 54,000
Division 7-Thermal and Moisture Protection
Sealants and Caulking 1 LS $ 3,000 $ 3,000
Interior Vinyl Siding 4000 SF $ 3 $ 12,000
Rigid Insulation 4400 SF $ 4 $ 15,400
Drywall 3200 SF $ 3 $ 9,600
LP CanExel Exterior Siding 3000 SF $ 4 $ 12,000
Subtotal $ 52,000
Division 8-Openings
Double Door Pump Building 21 EA 1 $ 5,000 $ 10,000
Wetwell Hatches 61 EA 1 $ 3,5001 $ 21,000
Subtotal $ 31,000
Division 9-Finishes
High Performance Wetwell Coating 30001 SF 1 $ 20 1 i
60,000
Subtotal 60,000
Division 10-Specialties
Hoist 1 EA $ 5,000 5,000Gantry 1 EA $ 5,000 5,000Bridge Crane 1 EA $ 50,000 50,000Subtotal 50,000
Division 23-HVAC
HVAC Equipment and Piping 11 LS 1 $ 50,000 1 $ 50,000
Subtotal $ 50,000
Division 26-Electrical
Electrical Work 11 LS 1 $ 276,877 $ 276,877
SCADA Connections 11 LS 1 $ 193,814 $ 193,814
Subtotal $ 470,691
Division 31-Earthwork
Landscape/Site Restoration 1 LS $ 15,000 $ 15,000
AC Paving 500 SY $ 60 $ 30,000
Wetwell Excavation 700 CY $ 15 $ 10,500
Shoring 1 LS $ 15,000 $ 15,000
Pump Building Excavation 75 CY $ 15 $ 1,125
Subtotal $ 71,625
Division 40-Process Interconnections
12"90'Elbow 151 EA 1 $ 500 1 1$ 7,500
12"45'Elbow 9 EA $ 450 $ 4,0 00
18"90'Elbow 4 EA $ 1,125 $ 4,500
18"45'Elbow 1 EA $ 900 $ 900
12"Check Valve 5 EA $ 6,000 $ 30,000
12"Gale Valve 7 EA $ 4,000 $ 28,000
Valve Controller 2 EA $ 12,500 $ 25,000
Miscellaneous Process 1 LS $ 10,000 $ 10,000
Air Relief Valve 2 EA $ 2,500 $ 5,000
Reducer 5 EA $ 1,125 $ 5,625
18"Tee 7 EA $ 2,250 $ 15,750
Potable Water Piping 1 LS $ 3,000 $ 3,000
18"Flow Meter 2 EA $ 6,750 $ 13,500
18"DI Piping 25 LF $ 413 $ 10,313
12"DI Piping 4251 LF 1 $ 150 $ 63,750
Subtotal $ 226,885
Divison 46-Water and Wastewater Equipment
Duty Pump 2 EA $ 105,000 $ 210,000
Jockey Pump 1 EA $ 75,000 $ 75,000
Pump Shipping 3 EA $ 3,700 $ 11,100
Generator and Transfer Switch 1 EA $ 117,654 $ 117,654
VFD Control Panel 1 EA $ 90,000 $ 90,000
Subtotal $ 503,754
Subtotal $ 1,977,880
1llobilization,Bonds&Insurance 8% S 158,000
Contractor's Overhead and Profit I5% S 297,000
Subtotal S 2,433,000
Montana Public Work's Tax 1% S 24,000
Subtotal $ 2,457,000
Miscellaneous Items and Contingencies 20% $ 491,000
Total Estintated Project Cost S 2,948,000
Appendix 6
SRF Environmental Requirements for PER
Submittal
41
UNIFORM ENVIRONMENTAL CHECKLIST
As the engineer that prepared the preliminary engineering report, I Coralynn Revis
(print name of engineer)
have reviewed the information presented In this checklist and believe that It accurately Identifies the
environmental resources in the area and the potential impacts that the project could have on those
resources. In addition,the required state and federal agencies were provided with the required information about
the project and requested to provide comments on the proposed public facility project. Their comments have been
incorporated into and attached to the Preliminary Engineering Report.
Engineer's Signature: Date: Z
Key Letter: N—No Impact B—Potentially Beneficial A—Potentially Adverse
P— Approval/Permits Required M—Mitigation Required
PHYSICAL ENVIRONMENT
Key 1. Soil Suitability, Topographic and/or Geologic Constraints (e.g., soil slump, steep
N slopes, subsidence, seismic activity)
Comments and Source of Information:
Key 2. Hazardous Facilities (e.g., power lines, EPA hazardous waste sites, acceptable
N distance from explosive and flammable hazards including chemical/petrochemical
storage tanks, underground fuel storage tanks, and related facilities such as natural
gas storage facilities & propane storage tanks)
Comments and Source of Information:
Key 3. Effects of Project on Surrounding Air Quality or Any Kind of Effects of Existing Air
N Quality on Project(e.g., dust, odors, emissions)
Comments and Source of Information:
Key 4. Groundwater Resources&Aquifers (e.g., quantity, quality, distribution, depth to
B groundwater,sole source aquifers)
Comments and Source of Information: Sewering this portion of the City will reduce the num 16
Key 5. Surface Water/Water Quality, Quantity & Distribution (e.g., streams, lakes,storm
N runoff, irrigation systems, canals)
Comments and Source of Information: The wastewater will be highly treated before being di�
Key 6. Floodplains & Floodplain Management(Identify any floodplains within one mile of the
N boundary of the project.)
Comments and Source of Information: The lift station is located on the City of Bozeman's
Key 7. Wetlands Protection (Identify any wetlands within one mile of the boundary of the
A project.)
Comments and Source of Information: Wetland delineation is part of the project and permittilill
Key Letter: N—No Impact B—Potentially Beneficial A—Potentially Adverse
P— A roval/Permits Required M—Mitigation Required
Key 8. Agricultural Lands, Production, & Farmland Protection (e.g., grazing,forestry,
N cropland, prime or unique agricultural lands) (Identify any prime or important farm
ground or forest lands within one mile of the boundary of the project.)
Comments and Source of Information:
Key 9. Vegetation &Wildlife Species& Habitats, Including Fish (e.g.,terrestrial, avian and
N aquatic life and habitats)
Comments and Source of Information:
Key 10. Unique, Endangered, Fragile, or Limited Environmental Resources, Including
N Endangered Species(e.g., plants,fish,sage grouse,or other wildlife)
Comments and Source of Information:
Key 11. Unique Natural Features (e.g., geologic features)
N
Comments and Source of Information:
Key 12. Access to, and Quality of, Recreational&Wilderness Activities, Public Lands and
Waterways(including Federally Designated Wild &Scenic Rivers), and Public Open
N Space
Comments and Source of Information:
HUMAN POPULATION
Key 1. Visual Quality-Coherence, Diversity, Compatibility of Use and Scale,Aesthetics
N
Comments and Source of Information:
Key 2. Nuisances (e.g., glare,fumes)
N
Comments and Source of Information:
Key 3. Noise--suitable separation between noise sensitive activities (such as residential
N areas) and major noise sources (aircraft, highways& railroads)
Comments and Source of Information:
Key 4. Historic Properties,Cultural,and Archaeological Resources
N
Comments and Source of Information:
Key Letter: N—No Impact B—Potentially Beneficial A—Potentially Adverse
P— Approval/Permits Required M—Mitigation Required
Key 5. Changes in Demographic (population)Characteristics (e.g., quantity, distribution,
B density)
Comments and Source of Information: Project will serve the growing population and resider
Key 6. Environmental Justice— (Does the project avoid placing lower income households in
areas where environmental degradation has occurred, such as adjacent to brownfield
N sites?)
Comments and Source of Information:
Key 7. General Housing Conditions-Quality, Quantity,Affordability
N
Comments and Source of Information:
Key 8. Displacement or Relocation of Businesses or Residents
N
Comments and Source of Information:
Key 9. Public Health and Safety
B
Comments and Source of Information: Project will improve wastewater collection infrastruct
Key 10. Lead Based Paint and/or Asbestos
N
Comments and Source of Information:
Key 11. Local Employment& Income Patterns -Quantity and Distribution of Employment,
Economic Impact
N
Comments and Source of Information:
Key 12. Local &State Tax Base& Revenues
N
Comments and Source of Information:
Key 13. Educational Facilities -Schools, Colleges, Universities
B
Comments and Source of Information: Project will provide wastewater collection infrastructlu
Key 14. Commercial and Industrial Facilities - Production &Activity, Growth or Decline
N
Comments and Source of Information:
Key Letter: N—No Impact B—Potentially Beneficial A—Potentially Adverse
P— A roval/Permits Required M—Mitigation Required
Key 15. Health Care—Medical Services
B
Comments and Source of Information: Project will provide wastewater collection infrastructlu
Key 16. Social Services—Governmental Services(e.g., demand on)
N
Comments and Source of Information:
Key 17. Social Structures& Mores(Standards of Social Conduct/Social Conventions)
N
Comments and Source of Information:
18. Land Use Compatibility(e.g., growth, land use change,development activity,adjacent
Key land uses and potential conflicts)
B
Comments and Source of Information: Provide sewer that supports development
Key 19. Energy Resources -Consumption and Conservation
N
Comments and Source of Information:Will require electricity to run lift station pumps; projec
Key 20. Solid Waste Management
B
Comments and Source of Information: The project will significantly improve the wastewater
Key 21. Wastewater Treatment-Sewage System
B
Comments and Source of Information: Project will allow new residential developments in N
Key 22. Storm Water—Surface Drainage
N
Comments and Source of Information:
Key 23. Community Water Supply
N
Comments and Source of Information:
Key 24. Public Safety—Police
N
Comments and Source of Information:
Key 25. Fire Protection—Hazards
N
Comments and Source of Information:
Key Letter: N—No Impact B—Potentially Beneficial A—Potentially Adverse
P— Approval/Permits Required M—Mitigation Required
Key 26. Emergency Medical Services
N
Comments and Source of Information:
Key 27. Parks, Playgrounds, &Open Space
N
Comments and Source of Information:
Key 28. Cultural Facilities, Cultural Uniqueness & Diversity
N
Comments and Source of Information:
Key 29. Transportation Networks and Traffic Flow Conflicts (e.g., rail; auto including local
N traffic; airport runway clear zones -avoidance of incompatible land use in airport
runway clear zones)
Comments and Source of Information: Project may cause temporary impacts to a small sec
Key 30. Consistency with Local Ordinances, Resolutions, or Plans (e.g., conformance with
B local comprehensive plans,zoning, or capital improvement plans)
Comments and Source of Information: The need for the Davis Lane Lift Station Project was
Key 31. Is There a Regulatory Action on Private Property Rights as a Result of this Project?
(consider options that reduce, minimize, or eliminate the regulation of private
N property rights.)
Comments and Source of Information:
Letter to State Agencies
May 22, 2019
Montana Department of Environmental Quality
Permitting and Compliance Division
1520 E. 611 Avenue, PO Box 200901
Helena, MT, 59620-0901
Dear Montana Department of Environmental Quality,
The City of Bozeman is applying for funding from the State Revolving Fund (SRF)for the
construction of the Davis Lane Lift Station and its associated project components.The
Uniform Application for Montana Public Facility Projects requires that we submit
information to you and ask for your comments on the proposed project.
Included in this letter is a map of the project area and a narrative description of the
project's principal elements. We would appreciate receiving your comments as soon as
possible.
I would appreciate it if your response is emailed to me at Coralynn.Revis@hdrinc.com. If
you have any questions, please contact me at (406) 532-2219 or the above listed email
address. If you have no concerns or comments regarding the described project, this letter
can be returned with the box checked at the bottom of this page.
Thank you very much for your assistance.
Sincerely,
Coralynn Revis, P.E.
To provide confirmation of support for this project, check the adjacent box and return. Elhdrinc.com
700 SW Higgins AvenueSuite 200Missoula,MT 59803-1489
(406)532-2200
Project Narrathf
The City of Bozeman is currently experiencing rapid residential growth. Consequently, several
portions of the City's wastewater collection system are at risk of becoming deficient as the
residential population increases. Much of the northwest portion of the City falls into this
category. This area of the City is the planned site for a new high school and the Billings Clinic,
both of which will be sources of large flows into the City's wastewater collection system. It will
be necessary to upgrade the wastewater infrastructure in this portion of the City before these
new connections come on line in fall of 2020.
The Davis Lane Lift Station project will address this growth, and will ultimately include the
construction of the Norton East Ranch Outfall Sewer, a new lift station and wetwell, and a force
main from the lift station to the City of Bozeman Water Reclamation Facility.
The preliminary project design consists of a single, self-cleaning style wetwell and lift station,
with two 18in force mains, on the north side of 1-90. The initial pumps installed in the wetwell will
be sized for the expected startup flows and then replaced once flows increased above the pump
model's capacity. This pumping design will help to manage the wide range of expected influent
flows over the lifespan of the lift station.
Figure 1 below outlines the expected locations of the various project components.
PROPOSED
SEWER
nRO MAW
ROUTE
OWN-41,
r I'7
I I U U N420RD \
O�lINN1IY ClF
1T64 CVEEK `: `'.
crtv of
BOZEMAN
FUTURE SEWER MA - \ WWTP
W
FXTH SIIONLANIE
' 7 1
y J PROPOSEDO �COH lON
- -. TO
ED SEWER MAW TO
111RE DEVELOPMENT
0` ALUt1.:NORTH 277H AVENUE
N-111
Figure 1.Project Location Overview
Agency Responses
Grover, Ted
From: Revis, Coralynn
Sent: Thursday,August 8, 2019 1:28 PM
To: Grover,Ted
Subject: FW: Davis Lane Lift Station
Coralynn Revis, PE
D 406.532.2219
hdrinc.corn follow-us
From:O'Neill, Deb [mailto:DONeill@mt.gov]
Sent:Thursday,August 8, 2019 1:28 PM
To: Revis, Coralynn <Coralynn.Revis@hdrinc.com>
Subject: Davis Lane Lift Station
Thank you for the opportunity to review this project.We have no comments.
Deb O'Neill
Deb O'Neill
Planning and Policy Specialist
Responsive Management Unit
Montana Fish,Wildlife & Parks
P.O. Box 200701
Helena, MT 59620-0701
Ph: (406)444-3755 1 C: (307) 231-3881
Montana FWP I Montana State Parks ( Montana Outdoors Magazine
THE OUTSIDE IS IN US ALL.
'w
.'
1
{ s 11i' u DEPARTMENT OF THE ARMY
CORPS OF ENGINEERS,OMAHA DISTRICT
t' HELENA REGULATORY OFFICE
10 WEST 15TH STREET,SUITE 2200
HELENA,MONTANA 59626
REPLY TO
ATTENTION OF
June 10, 2019
Regulatory Branch
Montana State Program
Corps No. NWO-2019-00955-MTB
Subject: City of Bozeman — Davis Lane Wastewater Lift Station
City of Bozeman
c/o
HDR, Inc.
Attn: Coralynn Revis
700 SW Higgins Ave., Suite 200
Missoula, Montana 59803
Dear Ms. Revis:
We are responding to your request for comment on behalf of the City of Bozeman
regarding the Davis Lane Wastewater Lift Station project in Gallatin County, Montana. The
project includes the proposed construction of a wetwell and lift station, with two 18-inch force
mains. The project site is adjacent to Cattail Creek, Catron Creek and the East Gallatin River,
and wetlands are likely present within the project boundary. The project is located at Latitude
45.724112°, Longitude-111.0822230, Section 26, Township 1 S, Range 5 E, Bozeman, Gallatin
County, Montana.
The mission of the U.S. Army Corps of Engineers (Corps) Regulatory Program is to
protect the Nation's aquatic resources while allowing reasonable development through fair,
flexible and balanced permit decisions. In particular, under Section 404 of the Clean Water Act,
we work to protect the biological, physical, and chemical integrity of the Nation's aquatic
resources. Projects are evaluated on a case-by-case basis to determine the potential benefits
and detriments that may occur as a result of the proposal. In all cases an applicant must avoid
and minimize impacts to aquatic resources to the greatest extent practicable.
Under the authority of Section 404 of the Clean Water Act (CWA), Department of the
Army (DA) permits are required for the discharge of fill material into waters of the U.S.
Likewise, DA permits are required for excavation activities resulting in a redeposit of dredged
material that would destroy or degrade waters of the U.S., per 33 CFR 323.2(d)(3). Waters of
the U.S. include the area below the ordinary high water mark of stream channels and lakes or
ponds connected to the tributary system, and wetlands adjacent to these waters. Isolated
waters and wetlands, as well as man-made channels, may be waters of the U.S. in certain
circumstances, which must be determined on a case-by-case basis.
Based on the information provided in your submittal, it appears that jurisdictional waters
of the U.S. may be present within the project area and would be impacted by the proposed
work. If the final design includes the placement of fill or dredged material in any of the
jurisdictional areas described in the paragraph above, or otherwise requires authorization by a
DA permit, please submit a permit application to this office prior to starting any work. We
recommend that an aquatic resources delineation be completed in accordance with the 1987
Corps of Engineers Wetlands Delineation Manual and appropriate regional supplement(s) to
Printed on Recycled Paper
-2-
ascertain the existence and extent of aquatic resources onsite. Any loss of an aquatic site may
require mitigation. Mitigation requirements will be determined during the Department of the
Army permitting review. After a review of the materials submitted we will determine what type of
permit, if any, will be required. In order to provide the necessary information you may use the
Montana Joint Permit Application Form, found at: http://www.dnrc.mt.gov/licenses-and-
permits/stream-permitting. If you do not wish to use this form, or do not have internet access
please contact our office at the address below to obtain more information.
Note that this letter is not a DA authorization to proceed. It only informs you of your
need to obtain a DA permit if waters of the U.S. will be affected. If waters of the U.S. will not be
affected by a jurisdictional activity a DA permit will not be required for the project.
Please refer to identification number NWO-2019-00955-MTB in any correspondence
concerning this project. If you have any questions, please contact me at Post Office Box 7032,
Billings, Montana 59103, by email at Marena.A.GilbertCaD-usace.army.mil, or telephone at (406)
657-5912.
Sincerely,
Marena A. Gilbert
Regulatory Project Manager
Copy Furnished:
Becky Clements, Gallatin Conservation District, via email at admin@gallatin.org
Printed on®Recyded Paper
Grover, Ted
From: Revis, Coralynn
Sent: Monday,June 3, 2019 1:38 PM
To: Grover,Ted
Subject: FW: CITY OF BOZEMAN SRF, DAVIS LANE LIFT STATION CONSTRUCTION
Attachments: 2019052903.pdf; CRABS.PDF;CRIS.PDF
Please look through and file this
Coralynn Revis, PE
D 406.532.2219
hdrinc.com/follow-us
From: Murdo, Damon [mailto:dmurdo@mt.gov]
Sent: Monday,June 3, 2019 1:33 PM
To: Revis, Coralynn<Coralynn.Revis@hdrinc.com>
Subject: CITY OF BOZEMAN SRF, DAVIS LANE LIFT STATION CONSTRUCTION
BigSky.Big Land.Big History.
Montana
�Historieal Society
June 3, 2019
Coralynn Revis
HDR
700 SW Higgins Ave,Suite 200
Missoula MT 59803
RE: CITY OF BOZEMAN SRF, DAVIS LANE LIFT STATION CONSTRUCTION. SHPO Project#: 2019052903
Dear Coralynn:
I have conducted a cultural resource file search for the above-cited project located in Section 27,T1S R5E.According to
our records there have been a few previously recorded sites within the designated search locale. In addition to the sites
there have been a few previously conducted cultural resource inventories done in the areas. I've attached a list of these
sites and reports. If you would like any further information regarding these sites or reports,you may contact me at the
number listed below.
It is SHPO's position that any structure over fifty years of age is considered historic and is potentially eligible for listing
on the National Register of Historic Places. If any structures are to be altered and are over fifty years old,we would
recommend that they be recorded, and a determination of their eligibility be made prior to any disturbance taking place.
As long as there will be no disturbance or alteration to structures over fifty years of age we feel that there is a low
likelihood cultural properties will be impacted.We,therefore,feel that a recommendation for a cultural resource
inventory is unwarranted at this time. However,should structures need to be altered or if cultural materials be
inadvertently discovered during this project we would ask that our office be contacted,and the site investigated.
1
If you have any further questions or comments,you may contact me at(406)444-7767 or by e-mail at dmurdo@mt.gov.
I have attached an invoice for the file search.Thank you for consulting with us.
Sincerely,
Damon Murdo
Cultural Records Manager
State Historic Preservation Office
File: DEQ/AWWM/2019
2
Grover, Ted
From: Revis, Coralynn
Sent: Tuesday,June 11, 2019 4:45 PM
To: Grover,Ted
Subject: FW: Davis Lane Lift Station
Coralynn Revis, PE
D 406.532.2219
hdrinc.com/follow-us
From: Davies,Jess [mailto:jess_davies@fws.gov]
Sent:Tuesday,June 11, 2019 4:45 PM
To: Revis, Coralynn<Coralynn.Revis@hdrinc.com>
Cc:Jeff Berglund <jeff_berglund@fws.gov>
Subject: Davis Lane Lift Station
Ms. Revis:
Thank you for your May 22, 2019 letter and supporting material requesting U.S. Fish and Wildlife Service comment on
the proposed subject project in Bozeman, Montana.
This email represents our official response to your inquiry for your records.
The U.S. Fish and Wildlife Service reviewed the maps and project description and has no comments or concerns
regarding federally-listed or proposed threatened or endangered species.
Thank you for the opportunity to comment. If you have any questions or comments about this correspondence please
contact Jess Davies at jess davies@fws.gov or 406-449-5225, extension 214.
Jess Davies
Fish and Wildlife Biologist
U.S. Fish and Wildlife Service
Montana Ecological Services Offices
585 Shepard Way, Suite i
Helena,Montana 596oi
(406) 449-5225 ext 214
i